JPH0413262A - Rotary head device - Google Patents

Abstract

PURPOSE:To stably connect slidably a recording medium with a recording and reproducing head by assembling a spiral group from which the inside air between a rotary drum and a fixed drum is blown off in a drum forming in a separate member, and forming an air path part at a drum side conforming to the spiral group. CONSTITUTION:The device is a rotary head device equipped with the rotary drum 2 and the fixed drum 5, and a pump-out type spiral group 11 is assembled in at least either the drums 2, 5 forming in the separate member, and the air path part 12 conforming to the spiral group 11 is formed on at least one side of two peripheral edge plane parts sandwiching a fine gap between both drums 2, 5. In such a case, the air in both drums 2, 5 blow off from the fine gap through the air path part 12 by the spiral group 11 in a state with extremely low pressure loss and low leakage, etc. Thereby, air film can be formed uniformly between the drum and a feeding tape shape recording medium.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a rotary head device used in a magnetic recording/reproducing device such as a video tape recorder (VTR).

[Summary of the invention]

According to the present invention, a spiral groove is formed as a separate member and incorporated into either the rotating drum or the fixed drum, and an air path portion corresponding to the spiral groove is formed on at least one of the peripheral surfaces of both drums sandwiching a small gap therebetween. In addition, the air inside the drum is smoothly discharged from minute gaps to form a uniform and stable air film, and the spiral groove can be easily formed, leading to cost reduction.

[Conventional technology]

Conventionally, a rotating head device used in a VTR has a structure in which a recording/reproducing head is held by a rotating drum, this rotating drum is attached to a rotating shaft, and this rotating shaft is supported by a fixed drum via a bearing. .

The magnetic tape, which serves as a tape-shaped recording medium, is wound around the outer peripheral surfaces of a rotating drum and a fixed drum, and is guided by the fixed drum and travels. Recording and playback are performed on the tape.

By the way, when the magnetic tape is wound around the circumferential surface of the rotary head device and is being run, the rotation of the magnetic tape causes it to float on the rotary drum side due to the formation of an air film.
On the fixed drum side, it runs in contact with the outer peripheral surface of the drum,
The flying height of the magnetic tape on the rotating drum side is related to the position of the magnetic tape on the rotating drum in the circumferential direction, and the flying height on the entrance side half circumference is larger than the flying height on the exit side half circumference. The change in flying height from the inlet side to the outlet side decreases almost linearly.

For this reason, the magnetic tape tends to separate from the tip of the recording/reproducing head, while the flying height is small in the half circumference on the exit side, causing it to wrap around the recording/reproducing head, causing the magnetic tape and the recording/reproducing head to become separated from each other. There is a risk that an unstable contact state may occur between the two and, therefore, signal transmission may also become unstable.

Therefore, in order to solve this problem, JP-A-62-2
As disclosed in Japanese Patent No. 39358, air is applied to at least a portion of the surface of the fixed cylinder facing the rotating cylinder from the population part where the magnetic tape is wound around the fixed cylinder to the exit part from the population side to the exit side. A rotary head device has been proposed in which a spiral groove is formed so that the liquid is ejected.

By configuring the rotary head device in this way, the amount of air discharged from the spiral groove increases from the entrance side to the exit side of winding the magnetic tape around the fixed cylinder, and the closer to the exit side the magnetic tape winds. In other words, an air film is formed between the magnetic tape and the cylinder, and a relatively stable contact state is obtained without the magnetic tape wrapping around the magnetic head. being done.

[Problem to be solved by the invention]

In order to efficiently form an air film between the rotating cylinder and the magnetic tape wound around the stationary cylinder as shown in 2, the two cylinders are placed on both sides facing each other with a small gap between them, or on either side of the magnetic tape. When forming a spiral groove for discharging air, the method of processing the spiral groove is an important factor in terms of productivity, cost, etc.

As for the processing method of this group, it is common to directly process the cylinder by NC (numerical control) machining, etching, etc., but in this case, since the cylinder is made of aluminum alloy, this process is This takes time and ends up being costly.

Therefore, it is conceivable to form the spiral groove from another material that is easy to process and incorporate it into the cylinder made of aluminum alloy.

The problem here is that in order to obtain a sufficient air discharge effect, the discharge ports of the group and the magnetic tape that is wound and run around the circumferential surface of the cylinder must be sufficiently close to each other.

However, when a separate member with a spiral groove is incorporated into the cylinder, the distance between the group's discharge port and the magnetic tape increases due to the structure, which causes air leakage and air pressure dispersion, resulting in insufficient air discharge. The force cannot be obtained, making it difficult to form the required air film between the cylinder and the magnetic tape.

That is, as shown in FIG. 10, when an annular member (43) made of, for example, a synthetic resin and having a required spiral groove (42) formed therein is incorporated into an aluminum alloy cylinder (41) such as a rotating cylinder or a stationary cylinder. Also, magnetic tape is used in cylinders (
41) and must not come into contact with the other annular member (43).
The outer circumferential surface of the cylinder (43) needs to be located inside the outer circumferential surface of the cylinder (41).

However, the outer peripheral surface of this cylinder (41) and the annular other member (
43), that is, when the thickness of the outer peripheral surface (41a) of the drum (41) is thick, the annular other member (4
3) This will hinder the air discharge from the spiral groove (42), and especially when the relative speed between the cylinder (41) and the magnetic tape is slow and the absolute amount of air discharged is small, an air film will not be formed. Therefore, it is necessary to reduce the wall thickness of the outer peripheral surface (41a) of this cylinder (41), but there is a limit to how thin this wall thickness can be.
It is difficult to achieve stable air film formation.

The present invention has been made in view of the above, and is a rotating head device that forms an air film by discharging air from a spiral groove. It is an object of the present invention to provide a rotating head device that facilitates the formation of a spiral groove and realizes a uniform and stable air film by forming an air path portion.

[Means to solve the problem]

In order to achieve the above object, the present invention includes a rotating drum that holds a recording/reproducing head, a fixed drum that rotatably supports the rotating drum with a small gap therebetween, and that guides a tape-shaped recording medium on its outer peripheral surface. A rotating head device comprising a pump-out type spiral groove formed as a separate member and incorporated in at least one of both drums, and corresponding to the spiral groove in at least one of both side edge portions sandwiching a minute gap between the two drums. An air path portion is formed.

[Effect]

In the present invention configured in this way, when the rotary drums rotate, the air in both drums is discharged from the minute gap through the air path section by the spiral groove, with extremely little pressure loss, leakage, etc. An air film is uniformly and stably formed between the tape-shaped recording medium that is wound around this and runs.

Further, by forming the spiral groove on a member separate from the drum, it becomes easier to process and form the spiral groove.

〔Example〕

Embodiments of the present invention will be described below with reference to FIGS. 1 to 9. First, a first embodiment will be described with reference to FIGS. 1 and 2.

In the figure, (1) shows the entire rotary head device;
2) is an upper drum as a rotating drum, which holds a recording/reproducing head (not shown), and this upper drum (2) is attached to a flange (4) fixed to a rotating shaft (3). 3) is pivotally supported by bearings (6) and (7) installed at the axial center of the lower drum (5) as a fixed drum so that a required gap a exists between it and the lower drum (5). is being done.

In this example, both drums (2) and (5) are installed on the lower surface side of the upper drum (2) and the upper surface side of the lower drum (5), respectively.
Annular members (8) and (9) formed of a different material, for example, a synthetic resin material, are fixed facing each other, that is, the annular member (8) fixed to the upper drum (2) is fixed to the upper drum (2). ) is located inside the lower peripheral edge part (2a) of the flange (4).
An annular member (9) fixed to the lower surface of ) and also fixed to the lower drum (5) is fixed to the upper surface of the annular member (8) and (9) located inside the peripheral surface portion (5a). ) are flush with the peripheral edge surface (2a) of the upper drum (2) and the peripheral edge surface (5a) of the lower drum (5), respectively.

And an annular member (8) fixed to the upper drum (2) side.
A pump-out type spiral groove (11) is formed on the opposing surface (8a), and a spiral groove is formed on the peripheral edge surface (2a) of the upper drum (2) located on the same plane on the outer peripheral side of the opposing surface (8a). A groove (12) serving as an air path is formed in the same direction as the spiral groove (11) so as to communicate with the groove (11). Meanwhile, the lower drum (
The opposing surface (9a) of the annular member (9) fixed to the ring member 5) is formed into an oblique plane.

In addition, both drums (2) are located near the bearing part of the lower drum (5).
.

(5) Ventilation hole (10) that communicates between the internal space and the outside
is drilled.

In this way, in this example, the upper drum (2) is provided with a separate annular member (8) having a spiral groove (11) formed therein.
), and by forming a groove (12) on the peripheral surface (2a) corresponding to the spiral groove (11) to provide an air path, the rotation of the upper drum (2) causes the respiral groove (11 ) is efficiently discharged from the small gap a between both drums (2) and (5) through the air path section with little pressure loss, leakage, etc., and this discharged air flows through both drums (2).

A floating blade is provided to the magnetic tape that is wound and run across the drums (5), and a uniform and stable air film is formed between both drums (2) and (5) and the magnetic tape, and the magnetic tape is Solid contact with both drums (2) and (5) is avoided, allowing stable sliding contact with the recording/reproducing head and smooth running.

In particular, when the relative speed between the rotation of the upper drum (2) and the running of the magnetic tape is slow, the amount of air discharged is small, making it more effective in this case.

The spiral group (11) is formed into an annular member (8) made of a drum and side material, such as a material that is easy to process and form, such as synthetic resin, so this process and formation is easy and cost-effective. .

FIG. 3 shows the rotating head device (of the first embodiment shown in FIG. 1).
This figure shows a modification of the upper drum (2) in 1).

That is, a groove (12) formed as an air path part communicating with a spiral groove (11) formed in an annular member [8] is formed on the peripheral edge surface (2a) of the upper drum (2).
2) is formed in the radial direction from the center.

In this way, forming the grooves (12) as air path sections in the radial direction means that the upper drum (2) is formed in this forming process.
) can be easily formed by cutting while rotating it by the required angle, which further improves workability and is more advantageous in terms of cost.

In the first embodiment including the above-mentioned variations, the spiral groove (11) is used as the upper drum (2) as a rotating drum.
This spiral groove (11) is formed on the side annular member (8), and the lower drum (5) serves as a fixed drum.
It may be formed on the opposing surface (9a) of the annular member (9) on the side, and the opposing surface (8a) of the annular member (8) on the upper drum (2) side may be formed into a flat surface.

The groove (12) as an air path portion is formed on the peripheral surface of the drum on the same plane side as the surface on which the spiral groove (11) is formed, that is, the spiral groove (11) is connected to the upper drum (2).
If the annular member (8) is formed on the side annular member (8), the annular member (9) on the lower drum (5) side is formed on the peripheral edge surface (2a) of the upper drum (2).
), the peripheral edge surface (5a) of the lower drum (5)
It is desirable to form a spiral groove (1
1) and the groove (12) may not be formed on the same plane side but may be formed on opposite sides. Further, the widths of the spiral groove (11) and the groove (12) serving as the air path portion do not need to be the same, and may be wider or narrower than each other.

Even in the relationship between the spiral groove (11) and the groove (12) as an air path part, the upper and lower drums (2)
(5) Internal air is efficiently discharged from the gap between the magnetic tape and the magnetic tape, and a uniform and stable air path can be formed between the magnetic tape and the magnetic tape.

Next, a rotary head device according to a second embodiment will be explained with reference to FIGS. 4 to 6.

In this example, six spiral grooves are arranged between an upper drum as a rotating drum to which a recording/reproducing head is attached and a lower drum as a fixed drum, and are formed in a rotary transformer for transmitting recording/reproducing signals. .

That is, in this example, as shown in FIGS. 4 to 6, the winding portion (2
3) has a spiral groove (11) formed on the outer peripheral side surface (22a) of the stator, which is fixed to the upper surface of the lower drum (5) as a fixed drum, and faces the rotor (22) with a required gap. Winding part (25) of (24)
The outer circumferential side surface (24a) of is formed into an oblate shape.

The rotor (22) of this rotary transformer (21) is similar to the annular member (8) fixed to the upper drum (2) side of the first embodiment described above. ) and is fixed to the lower surface of a flange (4) that attaches the upper drum (2) to the rotating shaft (3).
Further, the stator (24) is located on the upper surface of the lower drum (5) inside the peripheral surface (5a) and is fixed to the rotor (22) and the outer peripheral surface (22a) of the stator (24).
and (24a) are flush with the peripheral edge surface (2a) of the upper drum (2) and the peripheral edge surface (5a) of the lower drum (5), respectively.

Fig. 7 shows a modification of the rotary head device of the second embodiment shown in Figs. The outer circumferential side surface (22a) of the rotor (22), which is formed on the outer circumferential side surface (24&) of the stator (24) of the transformer (21) and is fixed to the upper drum (2) side, is formed in an oblate shape. It is.

Also in the case of the second embodiment including this modification, the upper drum (2
) or the peripheral edge surface portion (2a) of the lower drum (5) (
5a) A groove (
12).

In the second embodiment configured as described above, the upper drum (
2) is rotated, the internal air is discharged by the spiral groove (11) and the flat surface part, and this discharged air efficiently flows through both drums (12) as an air path part.
2), (5) The minute interval l! The magnetic tape is ejected from the magnetic tape 8 and provides a flying edge to the magnetic tape, allowing the magnetic tape to stably slide into contact with the recording/reproducing head and to realize smooth running.

In this second embodiment, the spiral groove (11) is connected to the rotor (21) of the rotary transfer (21).
22) or the winding part (23) of the stator (24) or (
Since molding can be performed at the same time as the winding groove molding in step 25), processing and forming is extremely easy, which is advantageous in terms of cost.

In addition, the rotary transformer (21) originally requires high precision for clearance, so forming a spiral groove (11) in it will provide assembly precision, and by measuring the inductance of the rotary transformer, the clearance value can be determined. Understand the upper and lower drums (
Since the gap a between 2) and (5) can be accurately set to a predetermined value, a highly accurate rotary head device can be obtained.

Further, a third embodiment of the rotary head device will be explained with reference to FIGS. 8 and 9.

In this example, a spiral groove is formed in a vertical rotary transformer disposed between an upper drum as a rotating drum to which a recording/reproducing head is attached and a lower drum as a fixed drum.

That is, in this example, as shown in FIG. 9, a cylindrical portion (4a) is provided on the flange (4) that attaches the upper drum (2) to the rotating shaft [3] on the inside of the upper drum (2). A rotor (32) of a vertical rotary transformer (31) is fixed to the outer peripheral surface of the portion (4a).
) is provided with a winding part (33) on the lower half circumferential surface, and the upper drum [
2), the upper half peripheral surface portion (32
a) A spiral groove (11) is formed in.

On the other hand, the lower drum (5) is formed into a cylindrical shape with a bottom, and has a stator (34) fixed to its inner peripheral surface in correspondence with the rotor (32) on the upper drum (2) side.
In (34), a winding part (35) is provided on the lower half curved surface corresponding to the winding part (33) of the rotor (32), and the upper part corresponds to the forming surface (32a) of the spiral groove (11). The half circumferential surface portion (34a) is formed into a flat surface.

A groove (12) serving as an air path is formed in the peripheral edge surface (2a) of the upper drum (2).

In this example configured in this way, the upper drum (2) is rotated and the rotary transformer (
31) rotor (32) (11+1 spiral groove (11) and stator (34) on the lower drum (5) side
The discharged air generated by the flattened surface (34a) of the upper drum (2) is efficiently discharged from the groove (12) serving as an air path section of the peripheral surface (2a) of the upper drum (2).
A uniform and stable air film is formed between the circumferential surface of (5) and the magnetic tape that is wound and run around it, allowing the magnetic tape to stably slide into contact with the recording/reproducing head and allowing smooth running. be done.

In this example as well, the spiral groove (11) may be formed on the stator (34) side of the rotary transformer (31), and the groove (12) as the air path portion may be formed on the lower drum (5) side as the fixed drum. It may be formed into

Also in this example, the spiral groove (11) can be molded at the same time as the winding groove of the rotor (32) or stator (34) of the rotary transformer (31). becomes extremely easy.

Although the present invention has been described in detail above, the present invention is not limited to these embodiments, and can be modified in various ways without departing from the spirit of the present invention.

〔Effect of the invention〕

As described above, according to the present invention, in the rotary head device, the spiral groove for discharging the internal air between the rotating drum and the fixed drum is formed as a separate member and incorporated into the drum, and the spiral groove is provided on the drum side corresponding to the spiral groove. By forming the air path part, it is possible to easily and accurately process and form the spiral groove, and it is possible to reliably generate discharge air and reduce pressure loss, leakage, etc. of this discharge air, so that the air can be routed between the drums. The air can be ejected efficiently from a minute gap, and a uniform and stable air film can be formed between the drum and the tape-shaped self-recording medium that is wound around the drum and travels, and the recording medium is stably attached to the recording/playback head. They are brought into sliding contact and run smoothly, ensuring reliable signal transmission, making it possible to record and reproduce high-quality images, especially in video tape recorders.

[Brief explanation of drawings]

FIG. 1 is a line sectional view of an example of a rotary head device according to the present invention, FIG. 2 is a bottom view of the rotary drum of the same device, FIG. 3 is a bottom view of a modified example of the rotary drum, and FIG. 5 is a bottom view of the rotating side drum of the device, FIG. 6 is an enlarged sectional view of the main part in FIG. 4, and FIG. 7 is a modified example of the same device. FIG. 8 is a cross-sectional view of still another example of the device of the present invention, FIG. 9 is a developed view of a portion of the same essential portion, and FIG. 1O is an explanatory diagram of a conventional example. In the figure, (2) is the upper drum (rotating drum), (2a) is the peripheral surface, (3) is the rotating shaft, (5) is the lower drum (fixed drum), (5a) is the peripheral surface, (8), (9) is an annular member, (11) is a spiral groove, (12) is a groove (air path portion'), and (21). (31) is a rotary transformer, (22), (32)
is the rotor, and (24) and (34) are the stators. Substitute Hitomatsu Hide Mori 2 Upper tram (ram on ward H wide) 5 Lower tsumu (ram on fixed) 5α Intersection ■Anya 6, LflFJ missing 11 Spiral groove f21 nose (F 1 space) Fig. 1 11 Bottom side of the upper drum (gut measurer ram) for men Figure 2 Whistle 3 Fig. 2 Section 4 Section 8 No. 9 ) 14 Air square roof f2 groove (Air J mass P) 21 Rotary transformer 22 Rotor 24 Stator Fig. 10

Claims (1)

[Scope of Claims] A rotary head device comprising a rotary drum that holds a recording/reproducing head, and a fixed drum that rotatably supports the rotary drum with a small gap and guides a tape-shaped recording medium on its outer peripheral surface. A pump-out type spiral groove is formed as a separate member and incorporated into at least one of the drums, and an air path corresponding to the spiral groove is formed on at least one of the peripheral surfaces of the drums sandwiching the minute gap. A rotary head device, characterized in that when the rotary drum rotates, air inside the drums is discharged from the minute gap through the air path portion by the spiral groove.